1. Field of the Invention
The present invention relates to a tightening device for a boot adapted to bring two adjustable parts thereof closer together and relates more specifically to a tightening device that can be adjusted in position on these parts in a direction transverse to that of the tightening force that it is capable of exerting by means of a tension lever with which it is provided.
2. Description of Background and Relevant Information
Tightening devices of the aforementioned type are described in German Publication Nos. 19 41 025 and 24 14 439, as well as in Swiss Patent No. 668 682. In these tightening devices, the relative position of the elements constituting them and connecting the adjustable parts of the boot can be adjusted in view of modifying the direction of the tightening force to be applied on these adjustable parts, and in view of respecting the morphology of the user's foot.
More specifically, in the example of DE 24 14 439, a tightening device has a tension lever with a baseplate that is adjustable in an angular position on a rigid notched plate fixed by rivets on one of the adjustable parts of the boot in the area of the instep girth. This lever is adapted to pull on a tie whose ends are connected to the same adjustable part of the boot as that which has the lever. Between these two ends, the tie takes support on two fixed returns located on the other adjustable part of the boot, another lever ensuring the adjustment of the active length of the tie and the opening-closing of the upper of the boot. According to a construction feature, the returns of the tie are fixed in position, one in the area of the upper and the other in the area of the toe-end of the foot, and it is the adjusting of the tension lever position on the rigid plate which modifies the direction of the tightening force. This tightening device is consequently adjustable in position with respect to the adjustable parts of the boot due to the notched plate, in the direction transverse to that of the tightening force that it exerts by means of the tension lever, the resulting force being directed to the area of the instep girth.
As this appears from this construction, there is no effective pulling on the adjustable part of the boot extending opposite of the tension lever in the area of the instep girth. Furthermore, given that the tie is retained at its two ends on one of the adjustable parts of the boot, and that it takes support on the other adjustable part by means of two returns between which the tension lever operates, the tightening force that the latter can produce is reduced by about twice as much in the area of the upper and of the toe-end of the foot. Consequently, to obtain the right tightening force in these areas, it is necessary to apply a very substantial force on the tension lever in the area of the instep girth. Moreover, it is not possible to adjust the tightening force at a preferred area of the boot. Finally, such a tightening device is complicated given the high number of parts that it has for retaining the baseplate of the tension lever on the plate and of the parts that it must use to obtain the actual tightening.
In the example of DE 19 41 025, the tightening device has two rigid slides which extend substantially parallel to one another and which are each fixed by rivets on one of the adjustable parts of the boot. An articulated assembly having a tension lever, to which is tied an adjustable tie rod, is slidably mounted by sectional end pieces on the two slides thus connected to one another. The tightening device is therefore adjustable in position on the adjustable parts of the boot by means of slides in a direction transverse, even perpendicular, to that of the tightening force that it exerts by means of the tension lever. This type of tightening device allows for an effective pulling on the adjustable part of the boot which extends opposite of the tension lever, and allows adjusting the tightening force with respect to the morphology of the user's foot. However, given that the articulated assembly does not have any positive stopping means with respect to the slides, it is susceptible of sliding thereon as soon as it is opened. In reality, to avoid any loss of adjustment, it is necessary to reposition it on the slides after each opening operation. In addition, when the tightening force is relatively weak, the articulated assembly with its lever can have an ill-timed sliding along the slides, even when it is closed. This tightening device proves to be relatively complex given the numerous pieces to be implemented at the level of the articulated lever assembly to allow adjusting the tension, and difficult to obtain as it involves making very specific sectional slides.
One solution to the above-mentioned type of problem is described in Swiss Patent No. 668 682. Indeed, the tightening device described is adjustable in position on one of the adjustable parts of the upper of the boot, in a direction transverse to that of the tightening force that it exerts by a tension lever, by means of a rigid insert provided with several fastening points on which the baseplate of a locking tie rod secured to the lever is positively fixed. In this type of tightening device construction, it is possible to adjust the tightening force with respect to the morphology of the user's foot, without having to reposition it after each opening operation. However, since it is adjustable in position only on one of the adjustable parts of the upper, therefore asymmetrically adjustable, the tightening device imposes, on all of the adjustable part of the boot without the insert, a relatively substantial general elastic deforming especially when the end fastening points are used. In addition, the direction of the tightening force also varies, but in a direction opposite of that of the adjusting done on the insert, unlike the devices previously disclosed. Indeed, in this type of tightening device, when the highest fastening point is used on the upper of the boot, it is on the lower edge of the upper that the tightening force is mainly exerted. Inversely, in a position of use of the lowest fastening point, it is on the upper edge of the upper that the tightening force is the highest. In fact, this device allows above all adapting the adjustable parts of the upper of the boot to the morphology of the lower part of the user's leg between two end positions where the upper takes on a conical shape, whether widened towards the top or widened towards the bottom.